condition mean min max ZT0-3 8.975732 8.975732 8.975732 ZT4-7 8.4778315 8.4778315 8.4778315 ZT8-11 8.4843775 8.4843775 8.4843775 ZT12-15 8.2880745 8.2880745 8.2880745 ZT16-19 8.8342885 8.8342885 8.8342885 ZT20-23 9.504773 9.504773 9.504773